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Granulite facies rocks provide important keys to evaluating collisional metamorphism in orogenic belts. The mafic granulites of Baoding in the Fuping Complex of the North China Craton occur within the Trans-North China Orogen (TNCO), a major Paleoproterozoic collisional orogen. Here, we present results from detailed investigations on newly discovered garnet pyroxenite, garnet two-pyroxene granulite, and garnet-bearing-plagioclase amphibolite using petrographic, mineralogical, geochemical, and zircon U-Pb dating methods. Our results show that the Fuping Complex metamorphic evolution in this study evolved in four stages: prograde (M1), high-pressure granulite facies (M2), granulite facies (M3), and retrograde (M4) stages. The mineral assemblage of the prograde stage (M1) consists of Amp + Pl + Q within garnet cores. The mineral assemblage of high-pressure granulite facies at the peak stage (M2) consists of Gt + Cpx + Pl + Q ± Amp, forming the garnet pyroxenite. The granulite facies stage M3 is characterized by the occurrence of orthopyroxene, with a mineral assemblage of Gt + Cpx + Opx + Amp+ Pl + Q. The early retrograde stage M4-1 includes clinopyroxenes scattered inside amphiboles, following the breakdown of garnet and clinopyroxene. The mineral assemblage of this stage comprises Amp + Pl + Q + Ilm ± Cpx. Later, in the late retrograde stage M4-2, the composition of amphiboles changed to actinolite, and epidote and chlorite started to appear in the matrix. Traditional geothermobarometry yielded P-T conditions of 700~706 °C and 6.0~6.2 kbar for prograde stage M1, 854~920 °C and 13.0~13.8 kbar for high-pressure granulite facies stage M2, 912~939 °C and 8.1~9.9 kbar for M3, 661~784 °C and 3.1~4.4 kbar for M4-1, and 637~638 °C, 1.1~1.3 kbar for M4-2, along a clockwise P-T path with a nearly isothermal decompression (ITD) and slight heating. Zircon LA-ICP-MS U-Pb dating constrains the timing of the high-pressure granulite facies metamorphic event to be between 1.83 and 1.86 Ga. Geochemical features suggest that the protoliths of the high-pressure granulites may have formed in an island arc environment within a convergent margin setting. Together with results from previous studies, our data suggest that the ~1.85 Ga metamorphic age recorded in the Fuping Complex represents a regional metamorphism in the TNCO, associated with the subduction–collision and assembly of the Eastern and Western Blocks of the NCC. [ABSTRACT FROM AUTHOR]

To ascertain the Early-to-Middle Jurassic tectonic setting in the central Great Xing'an Range, this study investigated the Early and Middle Jurassic granitoids exposed in the Chaihe area in the central Great Xing'an Range based on isotopic chronology and petrogeochemistry. The results of this study show that the Early and Middle Jurassic granitoids have emplacement ages of 179–172 Ma. Moreover, the Early and Middle Jurassic granitoids are high-K calc-alkaline unfractionated I-type granitoids and high-K calc-alkaline fractionated I-type granitoids, respectively. The magma sources of the Early and Middle Jurassic granitoids both originated from the partial melting of newly accreted lower crustal basaltic rocks. Meanwhile, the Middle Jurassic magma sources were mixed with mantle-derived materials or ocean-floor sediments formed by the dehydration and metasomatism of subducted slabs. The Early and Middle Jurassic granitoids in the study area were formed in the subduction environment of the oceanic crust, in which the Mongol-Okhotsk oceanic plate was subducted southward beneath the Eerguna and Xing'an blocks. Moreover, the Siberian plate began to collide and converge with northeast China during the Middle Jurassic. [ABSTRACT FROM AUTHOR]

The Jiao-Liao-Ji Belt (JLJB) is the most representative Paleoproterozoic orogenic belt in the North China Craton (NCC). The sedimentation, metamorphism and magmatism of the Ji'an Group and associated granites provide significant insights into the tectonic evolution of the JLJB. In this study, we have synthesized published geochemistry and geochronology data on metasedimentary, metavolcanic and igneous rocks. According to the available data, the protoliths of the metasedimentary rocks are sets of shale, wacke, arkose, quartz sandstone and carbonate, while the protoliths of the metavolcanic rocks are calc-alkaline basalt, basaltic andesite, andesite, dacite and rhyolite. The rock assemblages indicate a transformation of the tectonic environment from a passive margin to an active continental margin following the onset of plate convergence and subduction. The A2-type gneissic granite (Qianzhuogou pluton) is formed in a subsequent back-arc basin extension setting at 2.20–2.14 Ga. The Ji'an Group was finally deposited in an active continental margin during the closure of a back-arc basin at 2.14–2.0 Ga. Then, the sediments were involved in a continent–arc–continent collision between the Longgang and Nangrim blocks at ~1.95 Ga. This process was accompanied by HP granulite-facies metamorphism at ~1.90 Ga. The subsequent exhumation and regional extension resulted in decompression melting during 1.90–1.86 Ga, producing metamorphism with an isothermal decompression clockwise P–T path. The resulting metapelites are characterized by perthite + sillimanite, and mafic granulites are characterized by orthopyroxene + clinopyroxene. The S-type porphyritic granite (Shuangcha pluton) is formed during the crustal anatexis. Meanwhile, extensive anatexis produced significant heating and triggered prograde to peak metamorphism with an anticlockwise P–T path. Cordierite-bearing symplectites around the garnet in the metapelites indicate a superposed isobaric cooling metamorphism. The ages of monazites and anatectic zircons suggest that the post-exhumation cooling occurred at 1.86–1.80 Ga. The Paleoproterozoic magmatism, sedimentation and metamorphism suggest a process of subduction back-arc basin extension and closure, collision and exhumation for the tectonic evolution of the JLJB. [ABSTRACT FROM AUTHOR]

The tectonic setting of the Jiamusi–Khanka Massif in the eastern sector of the Central Asian Orogenic Belt (CAOB) in NE China is still highly controversial. This review considers all existing data to evaluate the origin of the Jiamusi–Khanka Massif. The Precambrian basement in the Jiamusi–Khanka Massif is dominated by the Neoproterozoic orthogneisses (898–891 and 757–751 Ma), the Mashan Complex (peak metamorphism at 530–500 Ma), and syntectonically deformed early Palaeozoic granitoids (530–484 Ma) related to the metamorphism of the Mashan Complex. The Mashan Complex reveals a clockwise orogen-style P–T path with peak conditions of 850–870°C/8–9 kbar followed by isothermal decompression. It was intruded by syn- (530–500 Ma) and post-tectonic (490–476 Ma) granitic rocks. The Jiamusi–Khanka Massif cannot be directly derived from the North China, South China, or Tarim cratons. Instead, it may have originated in the Siberian Craton and formed once part of the Altai-Sayan and Baikal orogens at ~500 Ma. For the Jiamusi Massif, we developed a plate tectonic model, and relate the final granulite facies metamorphism to slab break-off after consumption of a branch of the Palaeo-Asian Ocean. [ABSTRACT FROM AUTHOR]

The Mashan Complex of the Jiamusi Massif was traditionally considered as the oldest stratigraphic sequence in eastern NE China. However, the metamorphic degree of the Mashan Complex is different in different areas, which can be divided into Jixi–Mishan–Hulin granulite facies belt and Luobei–Huanan–Mudanjiang amphibolite facies belt. Here, we investigated the Mashan Complex in the Yilan area and present lots of new petrological, mineral chemical, geochemical, and U–Pb geochronological data, in addition to phase equilibria modelling, to constrain the timing of metamorphism, P–T conditions, and the P–T path of the Mashan Complex, and furthermore to deduce the crustal evolution of the Jiamusi Massif. The protoliths of the Mashan Complex in the Yilan area are greywackes and felsic sandstones, whose provenance is dominantly felsic rocks formed from a continental island arc. Petrographic observations, traditional thermobarometry, and quantitative phase equilibria modelling of the studied samples reveal P–T conditions from M2 to M3 of ~7.2 kbar/760–800°C and 4.5–5.0 kbar/585–610°C, respectively, which together define a clockwise P–T path involving decompressional cooling (M3) that followed the peak granulite‐facies metamorphism (M2). It reveals essential information related to the collision orogeny and post‐collision process. Zircon U–Pb dating of two felsic rocks yielded the peak of the granulite‐facies metamorphism in the Yilan area of the Jiamusi Massif that might have occurred at ~500 Ma. The overall deposition of the metamorphic rocks was later than ~760 Ma and that most of the detrital materials came from late Mesoproterozoic and early Neoproterozoic source rocks. [ABSTRACT FROM AUTHOR]

This article presents new zircon U–Pb ages, data on whole‐rock major and trace elements for the Early Ordovician to Early Cretaceous granitic rocks exposed in the Mohe Basin of North‐east China, and reveals the tectonic evolution history of the Mohe area during this period. The zircon U–Pb dating results indicate that the magmatic activities from the Early Ordovician to Early Cretaceous in the Mohe area can be divided into six stages, which are ~473, ~281, ~247, ~215, ~130, and ~124 Ma, respectively. The granitic rocks mainly originated by partial melting of a depleted and heterogeneous lower crust, except for the quartz diorites at ~130 Ma, derived from the separated crystallization of mantle‐derived subalkaline basaltic magma. The rock associations and their geochemical features indicate that the granitic rocks of ~247 and ~215 Ma formed in an active continental margin setting, whereas the granitic rocks with formation ages of ~473, ~281, ~130, and ~124 Ma were formed in an extensional tectonic setting. Each stage of magmatic activity is consistent with the magmatism and tectonism of the Erguna Block. Based on the achievements of the previous studies, we put forward a comprehensive tectonic evolution of the Mohe area. From Early Ordovician to Late Permian (473 ~ 252 Ma), the Mohe area was influenced by the Palaeo‐Asian Ocean tectonic domain. Magmatism of Late Permian to Late Jurassic (247 ~ 155 Ma) is mainly due to the subduction of the Mongol–Okhotsk Ocean. During the Late Jurassic, the Erguna Block collided with the Siberian Craton and the southern margin of the Siberian Craton was uplifted and started furnishing sediments into the Mohe Basin. In the Early Cretaceous (~130 Ma), the Mohe area may have been controlled by the Palaeo‐Pacific Ocean and the Mongol–Okhotsk Ocean tectonic domains. [ABSTRACT FROM AUTHOR]

The Mohe Basin, to the south of Mongol–Okhotsk suture belt (MOSB) closely, is a good window into investigations of the evolution of the Mongol–Okhotsk Ocean during the Late Mesozoic. Sandstone samples of the Upper Jurassic Series in the Mohe Basin, Mohe, and Kaikukang formations are studied in detail in terms of petrography, geochronology, and geochemistry. All samples have low compositional and textural maturity, which are located in the areas of dissected arc and basement uplift in Dickinson's discrimination diagrams. LA‐ICP‐MS U–Pb zircon dating yields the youngest concordant ages of 173 ± 4 Ma and 157 ± 3 Ma for the Mohe and Kaikukang formations, respectively, which constrain the maximum sedimentary periods of them. The peak ages of all concordant ages correspond identically to the regional magmatic activities on both the Siberian Craton and Erguna Block. All samples demonstrate geochemical characteristics not so different from the upper continental crust, whose provenance is felsic in lithology and is situated in active continental margins. Thus, a Mohe foreland basin and its binary provenance are strongly suggested, with the Erguna Block – a southern source and the Siberian Craton – a northern one. Based on all the evidence above, a simple tectonic model of the evolution of the Mongol–Okhotsk Ocean is raised, that is, from the Triassic to the Middle Jurassic; the Mongol–Okhotsk oceanic plate continued to subduct under the Siberian Craton and the Erguna Block, triggering intense magmatism in these areas. In the Late Jurassic, the rapid closure of the Mongol–Okhotsk Ocean caused the basement uplift and intense denudation which provided abundant sources of dissected arc and basement materials for the Mohe Basin. [ABSTRACT FROM AUTHOR]

Ultrahigh‐temperature (UHT) mafic granulites in the southern part of the Shiguai area in Daqingshan, China, crop out within the Shanheyuan Gneiss of the Khondalite Belt (KB), a Paleoproterozoic tectonic belt in the Western Block of the North China Craton (NCC). The UHT mafic granulites occur within hypersthene‐bearing dioritic–granitic gneiss as irregular lenses and deformed dike swarms. Four metamorphic generation assemblages (M1–M4) are recognized in the studied samples. M1 is defined by the enclosed orthopyroxene and clinopyroxene within the "red eye" corona of the garnet, representing the prograde metamorphic stage. M2 (UHT granulite‐facies) is marked by the appearance of "red eye" corona of the garnet, with mineral assemblages of grt–cpx–opx–pl–ilm–q. M3 is defined by spinel‐rich symplectites between garnet and orthopyroxene, including grt–opx–pl–spl–mt–ilm. M4 (amphibolite facies) is featured by the development of amphibole. Phase equilibrium modelling and some critical thermobarometers are combined to constrain the P–T evolution of the studied samples. The P–T conditions for the M1–M4 are respectively estimated at ~8 kbar/~771–852°C, ~9.4–10.0 kbar/~930–965°C, ~5.0–5.4 kbar/~865–910°C, ~5.0–5.2 kbar/~675–682°C, which define a clockwise P–T path, involving near‐isothermal decompression following the peak metamorphism. The P–T path indicates that the rocks underwent a sequence of tectonothermal processes that started with crustal thickening (M1–M2), followed by rapid crustal uplift (M3) and cooling (M4). This process is inferred that the metamorphism of the UHT mafic granulites was associated with rapid exhumation and uplift that followed the continent–continent collision and amalgamation of the Yinshan and Ordos blocks. This amalgamation formed the Paleoproterozoic KB in the Western Block of the NCC. [ABSTRACT FROM AUTHOR]

A new species Ufadendron elongatum sp. nov., attributed to the family Tomiodendraceae Naugolnykh, is represented by two well-preserved stems in the collection under study. This new species was recently discovered from the Upper Permian Linxi Formation in the Jalaid locality, the Inner Mongolia Autonomous region, China. The genus Ufadendron is characterized as having the long fusiform leaf cushions, with small and rounded leaf scar containing a central point-like scar which is situated at the upper part of leaf cushion; the infrafoliar bladder of fusiform shape positioned in the middle part of leaf cushion; the wings and heel well-developed in the lateral parts and the lower part of leaf cushion, respectively. The new species is different from the type species U. ufaense (Naugolnykh 2014) collected from the Lower Permian of the Cis- Urals, western limits of Angaraland, in the elongated leaf cushion and in the well-pronounced heel. It should be noted, that a vascular bundle (conductive strand) occupied the middle part of the central point-like scar. So far, only 5 genera of Angaran elements among lycopsids have been discovered in the region geographically belonging to Angaran Realm (Phytogeoprovince) in China. The new species U. elongatum not only enlarges our knowledge on the taxonomy of Tomiodendraceae lycopsids, and also provides an opportunity to understand the difference between Angaran and Cathaysian floras in paleoclimatic context. [ABSTRACT FROM AUTHOR]

The Jiutai area is tectonically situated at the eastern segment of the Central Asian Orogenic Belt (CAOB) and is close to the North China Craton (NCC) to the south, serving as an ideal place to investigations of the closure of the Paleo‐Asian Ocean (PAO). Sandstone samples collected from the Yangjiagou Formation and the Lujiatun Formation in this area have been studied in detail in terms of petrology, geochronology and geochemistry. The maximum depositional time of the Yangjiagou and Lujiatun formations has been constrained to early Middle Triassic (ca. 245 Ma) and middle Late Triassic (ca. 219 Ma), respectively. The Yangjiagou Formation, with a major provenance of dissected island arcs, is dominantly composed of Phanerozoic sediments from Northeastern China (NE China) massifs. The Lujiatun Formation, with major sediments from active continental margins, has a relatively larger proportion of Precambrian sediments, in which the ∼1.85 Ga and ∼2.5 Ga sediments are typical of the crystalline basements of the NCC and NE China massifs, which were uplifted and eroded during the closure of the PAO. Besides, both formations show the enrichment in LREEs and the depletion in HREEs, the common Eu negative anomalies, and trace element contents similar to that of the upper continental crust. Based on the provenance analysis of these two formations, the final closure time of the PAO in this area is constrained as from the early Middle Triassic (ca. 245 Ma) to the middle Late Triassic (ca. 219 Ma). [ABSTRACT FROM AUTHOR]

The Mohe Basin, to the south of the eastern Mongol–Okhotsk suture belt, contains important stratigraphic records and thrust‐nappe structures for understanding the closure of the eastern Mongol–Okhotsk Ocean. Meso‐micro structures in the Mohe Formation indicate a low‐temperature deformation/metamorphism (ca. 400°C) under an N‐S compression related to the southward thrusting faulting. The S‐L‐tectonites record strain similar or close to flattening/compressional strain and denote sinistral shearing in analogously N‐S‐trending thrusting. Our new detrital zircon U–Pb ages exhibit that maximum depositional ages of the Mohe Formation were conservatively estimated as latest Middle Jurassic (ca. 165 Ma). The Northeast China and Erguna Block to the south of the Mohe Basin, and Siberian Block to the north were the sources for the Mohe foreland basin's sediments throughout the deposition of the Mohe Formation, which derived from the basement uplift where erosion cuts deep into the dissected arcs. In the latest Jurassic to earliest Cretaceous, the southward collision and indentation of the Siberian Block (final closure of Mongol–Okhotsk Ocean) led to intense thrust nappe structures, syn‐collisional folds, and low‐temperature metamorphism occurred along the northwestern margin of Mohe Basin. [ABSTRACT FROM AUTHOR]

The nature and formation time of the Xinghuadukou complex in Northeast China are important for determining the tectonic evolution of the Precambrian geological evolution of the Erguna massif. In this study, we present the results of zircon U-Pb dating of two metapelites from the complex. Detrital and metamorphic zircons from the metapelites yield a depositional age of ~601 Ma and a metamorphic age of 496-509 Ma, indicating that the supracrustal rocks formed during the Neoproterozoic and recorded pan-African metamorphic events in the Erguna massif. Garnet porphyroblasts in Sil-Grt-Bt-Ms paragneiss show diffusion zoning, implying a decreasing P-T trend. Based on mineral transformation and P-T estimates using conventional geothermobarometers and phase equilibria modeling, three metamorphic stages were determined, including an early prograde metamorphic stage, a near peak upper amphibolite facies metamorphic stage, and a near-isobaric cooling stage with P-T conditions of 6.1 kb, 645 °C, 5-6 kb, 710-740 °C, and 4.4 kb, 625 °C, respectively. The metamorphic history of the Xinghuadukou complex is thus defined by a clockwise P-T trajectory, which implies that the metamorphism of the metapelites documented the subduction, subsequent uplift and post collision process. [ABSTRACT FROM AUTHOR]

Adakite‐like volcanic rocks in the Moguqi area of the central Great Xing'an Range of NE China consist of trachyandesites and trachydacites. These rocks yield LA–ICP–MS U–Pb zircon ages of 229.5–232.6 Ma. These adakite‐like rocks are high in Sr (459–1960 ppm) and MgO (1.2–4.3%), low in Y (11.4–23.70 ppm) and Yb (0.88–2.07 ppm), and have high Sr/Y ratios (37.17–146.31) and high Mg# values (0.43–0.58). These characteristics are similar to those of rocks derived from slab melting. However, the existence of Early Triassic stable continental sedimentary rocks of the Laolongtou Formation does not favour this mode of formation. The zircon εHf(t) values of the samples range from +8.09 to +13.29, indicating the primary magmas were generated by partial melting of juvenile crust. Analysis of geophysical data, combined with the previously published history of the Hegenshan–Heihe Suture in this region and the southward subduction of Mongol–Okhotsk oceanic plate, suggests that the Late Triassic adakite‐like volcanic rocks in the Xing'an Massif formed from the partial melting of delaminated thickened crust in an extensional setting. This occurred after orogenesis involving the Xing'an Massif and the Songnen Massif and was influenced by southward subduction of the Mongol–Okhotsk oceanic plate. [ABSTRACT FROM AUTHOR]

• Charnockites formed by granulite-facies metamorphism of A-type granites in the Badu Complex. • A clockwise P-T path with high-temperature peak conditions of 810-825 °C in the Charnockites. • Charnockites emplaced at 1.86 Ga and metamorphosed at 230 Ma. As the oldest basement rocks in the Cathaysia Block of South China, the Paleoproterozoic Badu Complex underwent high-grade metamorphism and preserved a suit of charnockites that their petrogenesis is still controversial. Comprehensive studies of petrology, mineral chemistry, metamorphic P-T calculation, and zircon U-Pb geochronology trend to discuss the petrogenesis of garnet-bearing charnockites from the Badu Complex in the Suichang-Dazhe area of southwestern Zhejiang Province in detail. The charnockites contain an assemblage of garnet, clinopyroxene, orthopyroxene, biotite, plagioclase, anti-perthite, K-feldspar, quartz, and ilmenite. Three metamorphic stages can be recognized: The prograde (M1) mineral assemblage is mainly composed of garnet (core) + biotite + clinopyroxene + plagioclase + quartz occurring as inclusions in garnet porphyroblast or pyroxene; The peak metamorphic (M2) mineral assemblage is identified as garnet (mantle) + clinopyroxene + orthopyroxene + biotite + plagioclase + K-feldspar + anti-perthite + ilmenite + quartz + melt, typical of granulite-facies mineral assemblage; minerals in plagioclase symplectic corona around garnet porphyroblast and replacing orthopyroxene constitute the retrograde assemblage (M3), including garnet (rim) + clinopyroxene + biotite + plagioclase + quartz ± Ilm. Conventional geothermobarometry in combination with phase equilibria modeling employing the NCKFMASHTO system yield metamorphic P-T conditions for each metamorphic stage as 810–825 °C, 7.5–8.3kbar (M2), 570–640 °C, 5.9–6.4 kbar (M3). It suggests that the charnockites experienced granulite-facies metamorphism and overprinted decompression and cooling along a clockwise P-T path. LA-ICP-MS zircon U-Pb data show a protolith age of 1860 ± 40 Ma and metamorphic age of 229.1 ± 5.7 Ma from the charnockites respectively. Combined with previous studies, we infer that the protolith of charnockites could be the Paleoproterozoic A-type granites and underwent granulite-facies metamorphism during the Indosinian orogenic event. Considering high-grade metamorphism and clockwise P-T path in charnockites with other metamorphic rocks in the Badu Complex, we suggest that the Indosinian orogenic event in the Cathaysia block could be attributed to continental collisions of South China with Indochina and North China. Significant underthrusting of Badu Complex along plate margins with subsequent rapid exhumation might be involved in this process, leading to granulite-facies metamorphism and later decompression and cooling in Paleoproterozoic basement rocks such as charnockites in the Suichang-Dazhe area. [ABSTRACT FROM AUTHOR]

• The Mashan Complex were involved in multiple-stage metamorphism. • Four generations of metamorphic mineral assemblages were recognized. • A clockwise P-T path with nearly isothermal decompression segments was established. • Peak of the granulite facies metamorphism might have occurred at ca. 530 Ma. The Mashan Complex is the oldest metamorphic rock series in the Jiamusi Massif, which consists mainly of amphibolite to granulite facies metamorphic rocks accompanied by various granitic rocks. Herein, we investigate the pelitic granulites from this complex as well as associated granites and identify four distinct mineral assemblages corresponding to different metamorphic stages. The prograde metamorphism (M 1) is recorded by the core of the garnet and inclusions within: Grt core –Bi–Sil–Qz. The peak granulite facies metamorphism (M 2) is distinguished by the garnet mantle and the related mineral assemblages in the matrix: Bi–Kfs–Grt mantle –Ilm–Sil–Qz. The post-peak decompression stage (M 3) is characterized by the formation of cordierite corona and minerals in the cordierite of the matrix: Bi–Liq–Crd–Pl–Kfs–Grt–Ilm–Sil–Qz–Mt. The retrograde stage (M 4) is featured by the garnet rim and the nearby assemblages: Bi–Crd–Pl–Kfs–Grt rim –Ilm–Sil–Qz–Mt. According to the phase equilibria modeling, the metamorphic P–T conditions from M 2 to M 4 were estimated as 6.5–8.5 kbar/815–825 °C, 5.3–5.7 kbar/780–795 °C, and 4.5–5.3 kbar/730–775 °C, respectively, which together define a clockwise P–T path. LA–ICP–MS U–Pb dating for zircons from four metamorphic rocks shows that most of the detrital material came from middle Paleoproterozoic, middle Mesoproterozoic and early Neoproterozoic source rocks. In addition, metamorphic zircon grains in the metamorphic rocks yield two groups of ages at ca. 530 Ma and ca. 500 Ma, which are regarded as the peak of granulite-facies metamorphic (M 2) and the retrograde cooling metamorphic (M 4) ages, respectively. [ABSTRACT FROM AUTHOR]

The Badu Complex is the oldest metamorphic rock in Cathaysia Block which experienced several episodes of metamorphism Especially indosinian metamorphic reworking in the southwestern Zhejiang Province, South China. The degree of indosinian metamorphism reaches granulite facies. However, there is still insufficient understanding of the characteristics of the Indosinian granulite metamorphism in the Cathaysia and many interpretations of its tectonic significance. Therefore, we present detailed petrology, mineral chemistry and LA‐ICP‐MS zircon U‐Pb age in this paper from pelitic granulites of the Badu Complex, which is composed of "sillimanite + garnet + cordierite + spinel + biotite + k‐feldspar" assemblage and garnet pyroxenite with garnet amphibolite which is consists of "garnet + clinopyroxene + orthopyroxene + amphibole + plagioclase". By comprehensive study we get following new findings: Pelitic granulites record four stages of metamorphic mineral assemblages, including prograde (M1), pressure peak (M2), Peak (M3) and post‐peak decompressional and then cooling (M4) stages. The prograde M1 assemblage consists of garnet1 (core) + staurolite + kyanite + biotite + quartz ± rutile ± chlorite; The pressure peak M2 assemblage consists of garnet1 (mantle) + sudoite + rutile + kyanite + corundum + biotite + quartz; The peak M3 have garnet2 (rim‐mantle) + biotite + sillimanite + quartz ± K‐feldspar ± plagioclase ± ilmenite assemblag; the M4 stage is consist of garnet + cordierite + biotite + sillimanite + quartz + ilmenite ± spine ± K‐feldspar. The garnet pyroxenite and garnet amphibolites have experienced three stages of metamorphic evolution. Peak high‐pressure granulite facies stage M2 consists of garnet + sahlite ± ilmenite ± quartz; Post‐peak near isothermal decompression medium granulite facies stage M3 is characterized by typical decompression reaction textures and assemblage of orthopyroxene + plagioclase (An=90–92); amphibolites facies retrograde metamorphic stage M4 is characterized by amphibole + plagioclase (An=33–35) + ilmenite ± sahlite ± quartz mineral assemblage. By means of phase equilibrium simulation and traditional thermobarometer, P‐T conditions of 785–820 °C and 8.9–9.9 kbar for M3 stage, 780–860 °C and 5.7–6.2 kbar for decompressional M4 stage, 705–720 °C and 4.5–4.7 kbar for cooling M4 stage in pelitic granulites were obtained. And also 11.6–12.5 kbar and 780–840 °C for M2 stage, 7.4–8.2 kbar and 800–880 °C for M3 stage, 6.6–7.5 kbar and 500–560 °C for M4 stage were obtained in garnet pyroxenite and garnet amphibolite. A clockwise P‐T path is confirmed in the two type rocks of the Badu Complex which reflected a near‐isothermal decompressional metamorphic process. The peak metamorphism can reach high‐pressure granulite facies. In addition, the mineral assemblage of garnet + rutile + kyanite + corundum in the peak metamorphic stage of pelitic granulite indicates that it may underwent ultra‐high‐pressure metamorphism, and the acidic plagioclase exsolution of clinopyroxene in garnet pyroxenite also suggests that it may be retrograded eclogites, which indicates that the deeper Cathaysian block may have eclogite metamorphism. Analyses of LA‐ICP‐MS zircon U‐Pb dating indicate that the metamorphic age of pelitic granulite is 233.5 Ma–subduction/collision followed by rapid exhumation and cooling events. The events may relate with the amalgamation of the Indochina Block‐South China Block North China Block in the paleo‐Tethyan domain. [ABSTRACT FROM AUTHOR]

• Four metamorphic generation assemblages were recognized in high-grade granulite facies rocks of the Mashan Complex. • A clockwise P-T path with nearly isothermal decompression segments was established. • The peak of the granulite facies metamorphism might have occurred at ca. 530 Ma, and its final cooling stage could take place at ca. 490 Ma. The nature and age of the Mashan Complex (or Mashan Group) in northeast China is key for determining the Precambrian geological evolution and origins of the Jiamusi Massif. Here we present a detailed investigation of high-grade granulite-facies rocks of the Mashan Complex from the Liumao area, Heilongjiang Province, China. This includes zircon U–Pb dating, petrological and geochemical analysis, geothermobarometry, phase equilibria modelling, and a P–T path. The metamorphic rocks consist mainly of two groups: pelitic and felsic granulites; amphibolite-facies Sil–Grt–Bi, Sil–Grt, and Grt–Bi gneisses. The protoliths of the metamorphic rocks were clay rocks and sandstones, which were derived dominantly from silicic rocks in a continental island arc setting. In the pelitic granulites, four metamorphic assemblages (M 1 –M 4) were recognised. Three metamorphic assemblages (M 2 –M 4) were identified in the felsic granulites. Geothermobarometric data and phase equilibria modelling indicate that the M 2 , M 3 , and M 4 assemblages in the pelitic granulite were metamorphosed at 9.2 kbar/845–865 °C, 4.7–5.1 kbar/820–865 °C, and 4.0–4.8 kbar/660–720 °C, respectively. These features imply a collisional orogenic process with a clockwise P–T path with nearly isothermal decompression segments. Similar results were obtained for the felsic granulite, with the metamorphic P–T conditions of the peak assemblage (M 2) evaluated as 9.0–9.2 kbar/845–870 °C. The similar P–T paths indicate that the rocks underwent an evolutionary process that started with crustal thickening (M 2), followed by rapid crustal uplift (M 3), and then final cooling (M 4). Based on our new zircon U – Pb age data, the peak of granulite-facies metamorphism in the Liumao area of the Jiamusi Massif occurred at ca. 530 Ma and final cooling occurred at ca. 490 Ma. [ABSTRACT FROM AUTHOR]

• A possible evolution model of Longgang and Langrim blocks is proposed. • Four metamorphism stages can draw from special mineral assemblages of the metapelites, which define a clockwise P-T-t path. • The protoliths of metapelite were formed around 1.95–2.02 Ga. And there was a regional metamorphism with widespread anatexis around 1.8–1.95 Ga. The Jiao–Liao–Ji Belt (JLJB) is an important Paleoproterozoic orogenic belt that has been a focus of research to understand the Precambrian evolution of the North China Craton (NCC). The widespread Paleoproterozoic Ji'an group, which was exposed in the northern margin of JLJB, is the key to solving controversies in the tectonic setting of this special belt. An intensive study on metamorphic reactions, zircon U–Pb ages, mineral thermobarometry, geochemistry, and quantitative phase equilibria modeling (pressure–temperature pseudosections) of typical metapelites from the Dadongcha Formation of the Ji'an group provides important insight to understand the tectonic setting and processes of the Paleoproterozoic JLJB. The analyzed metapelites are exposed in Toudao and Qinghe towns in NE China, include garnet–biotite schist, garnet–biotite–plagioclase gneiss, garnet–sillimanite–cordierite–biotite gneiss, and hypersthene-spinel–cordierite–biotite gneiss. Garnets contain mineral inclusions such as sillimanite, biotite, feldspar, and quartz and retain the typical cordierite reactive edge structures. The protoliths of metapelites are sets of claystone or miscellaneous sandstone with an average chemical composition that is close to that of the upper continental crust (UCC). Chemical Index of Alteration (CIA) and Index of Compositional Variability (ICV) values suggest a high degree of weathering of their sources and low compositional maturity of clastic sediments. The chondrite-normalized rare earth element (REE) pattern of analyzed samples displays characteristics of medium fractionation in light and heavy REEs, and strong enrichment in light REEs. The primitive mantle-normalized trace element pattern shows enrichment of large ion lithophile elements (LILEs) such as Ba, and the content of high field strength elements (HFSEs) such as Zr and Hf is relatively low; furthermore, Nb, Ta, P, and Ti are distinctly depleted. The emphasis is on the metamorphism of metapelites, which shows a clockwise P–T path. In combination with zircon U–Pb dating, a general evolution model for the metapelites was drawn. The metapelites were formed in an active continental margin environment where the evolved island arcs developed around 1.95–2.02 Ga, then were involved in the collision between the Longgang and Langrim blocks in the eastern part of the NCC, and returned to the surface after undergoing regional metamorphism with widespread anatexis around 1.8–1.95 Ga. [ABSTRACT FROM AUTHOR]

Objective: To investigate the association between dietary and some other environmental factors and the risk of inflammatory bowel diseases (IBD) in Chinese population., Materials and Methods: A multicenter case-control study was conducted involving 11 hospitals across China. A total of 1,230 subjects were enrolled consecutively, and diet and environmental factor questionnaires were collected. IBD patients were matched with healthy controls (HC) using propensity-score matching (PSM) at a 1:1 ratio with a caliper value of 0.02. Multivariate conditional logistic regression analyses were performed to evaluate the associations between diet, environmental factors, and IBD., Results: Moderate alcohol and milk consumption, as well as daily intake of fresh fruit, were protective factors for both Crohn's disease (CD) and ulcerative colitis (UC). Conversely, the consumption of eggs and chocolate increased the risk of IBD. Outdoor time for more than 25% of the day was a protective factor only for CD. In eastern regions of China, CD patients had higher egg consumption and less outdoor time, while UC patients consumed more chocolate. IBD patients from urban areas or with higher per capita monthly income consumed more fruit, eggs, and chocolate., Conclusions: This study reveals an association between specific foods, outdoor time, and the emergence of IBD in the Chinese population. The findings emphasize the importance of a balanced diet, sufficient outdoor time and activities, and tailored prevention strategies considering regional variations., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Chu, Chen, Zhang, Wang, Guo, Chen, Liu, Zhu, He, Ding, Wang, Zheng, Cao, Yang and Qian.)